Van Eerd, L. L., Congreves, K. A., Hayes, A., Verhallen, A. and Hooker, D. C. 2014. Long-term tillage and crop rotation effects on soil quality, organic carbon, and total nitrogen. Can. J. Soil Sci. 94: 303–315. Long-term studies allow for quantification of the effects of crop production practices, such as tillage and crop rotation, on soil quality and soil C and N stores. In two experiments at Ridgetown, ON, we evaluated the long-term (11 and 15 yr) effect of tillage system and crop rotation on soil quality via the Cornell Soil Health Assessment (CSHA) at 0–15 cm and soil organic C (SOC) and total N at 5-, 10-, and 20-cm increments to 120 cm depth. The CSHA soil quality score and SOC and total N were higher with no-till (NT) than fall moldboard plough with spring cultivation (conventional tillage, CT) and rotations with winter wheat [soybean–winter wheat (S-W) and soybean–winter wheat–corn (S-W-C)] compared with rotations without winter wheat. In both long-term trials, NT had ca. 21 Mg ha−1 more or 14% higher SOC than CT in the 0- to 100-cm soil profile, a trend which contrasts previous research in eastern Canada. Thus, the two long-term trial results at Ridgetown suggest that to improve soil quality and storage of C and N, growers on clay loam soil in southwestern Ontario should consider adopting NT production practices and including winter wheat in the rotation.

. 2015. Biologically effective rate of sulfentrazone applied pre-emergence in soybean. Can. J. Plant Sci. 95: 339Á344. Sulfentrazone is a protoporphyrinogen (PPO)-inhibiting herbicide under evaluation for use in soybean in Ontario, Canada. The primary objective of this study was to determine the dose of sulfentrazone applied pre-emergence (PRE) needed to provide 50 and 90% control of redroot pigweed, common ragweed, common lambsquarters and green foxtail. Seven field trials were conducted over a 3-yr period (2007, 2008 and 2009) in southwestern Ontario to evaluate the efficacy of sulfentrazone applied PRE at doses ranging from 26 to 1120 g a.i. ha The doses of sulfentrazone applied PRE to reduce redroot pigweed, common ragweed, common lambsquarters and green foxtail dry weight by 50% were 104, 139, 15 and 65 g a.i. ha(1 ; doses of 241, 514, 133 and 721 g a.i. ha (1 of sulfentrazone were required for 90% reduction in above-ground biomass of those weed species, respectively. Sulfentrazone applied PRE caused soybean injury only at 560 and 1120 g a.i. ha(1 , with 6 and 13% soybean injury at 4 wk after herbicide application (WAT), respectively. Weed control provided by sulfentrazone applied PRE at a dose of 600 g a.i. ha(1 was sufficient to maintain 90% of the soybean yield compared with the weed-free control. Therefore, PRE application of sulfentrazone has the potential to provide excellent (90%) control of selected weeds with minimal to no crop injury; however, weed control varied by species, and thus broad spectrum weed control is not feasible using sulfentrazone alone.

. 2015. Glyphosate and acetolactate synthase inhibitor resistant common ragweed (Ambrosia artemisiifolia L.) in southwestern Ontario. Can. J. Plant Sci. 95: 335Á338. Common ragweed (Ambrosia artemisiifolia L.) was found to be resistant to glyphosate in Ontario. Field surveys were conducted from 2011 to 2013 to determine the distribution of glyphosate-resistant (GR) and acetolactate synthase inhibitor resistant common ragweed. GR common ragweed was confirmed in Essex County. All GR populations were found to be resistant to acetolactate synthase-inhibiting herbicides.

Congreves, K. A., Smith, J. M., Németh, D. D., Hooker, D. C. and Van Eerd, L. L. 2014. Soil organic carbon and land use: Processes and potential in Ontario’s long-term agro-ecosystem research sites. Can. J. Soil Sci. 94: 317–336. Soil organic carbon (SOC) is crucial for maintaining a productive agro-ecosystem. Long-term research must be synthesized to understand the effects of land management on SOC storage and to develop best practices to prevent soil degradation. Therefore, this review compiled an inventory of long-term Ontario studies and assessed SOC storage under common Ontario land management regimes via a meta-analysis and literature review. In general, greater SOC storage occurred in no-till (NT) vs. tillage systems, in crop rotation vs. continuous corn, and in N fertilizer vs. no N fertilizer systems; however, soil texture and perhaps drainage class may determine the effects of tillage. The effect on SOC storage was variable when deeper soil depth ranges (0–45 cm) were considered for NT and rotational cropping, which suggests an unpredictable effect of land management on SOC at depths below the plough layer. Therefore, researchers are encouraged to use the presented inventory of nine long-term research sites and 18 active experiments in Ontario to pursue coordinated studies of long-term land management on SOC at depths extending below the plough layer.

. 2015. Optimizing inputs for winter durum wheat in Ontario. Can. J. Plant Sci. 95: 361Á368. Best management practices need to be determined for a new wheat class in Ontario: winter durum. The objectives of this study were to determine optimal nitrogen rates (75, 100, and 125 . Grain yields did not increase with N rates higher than 100 kg N ha(1 , and the response to N rate did not depend on the application of fungicides. Grain protein concentrations increased with N rates up to 125 kg N ha(1 , which was the highest N rate investigated in this study. An economic analysis is needed to determine the impact of agronomic management strategies specific to winter durum wheat in Ontario. Le rendement grainier n'augmente pas avec le taux d'application des engrais azote´s une fois que celui-ci de´passe 100 kg de N par hectare, et la re´action a`la quantite´d'engrais applique´e ne de´pend pas de l'usage de fongicides. La concentration de prote´ines dans le grain augmente avec le taux d'application des engrais N jusqu'a`125 kg de N par hectare, taux le plus e´leve´examine´dans le cadre de cette e´tude. Il faudrait entreprendre une analyse e´conomique pour ve´rifier l'impact des strate´gies agronomiques particulie`res a`la culture du ble´dur d'hiver en Ontario.